The present invention relates to hollow waveguide tips, particularly for lasers, and also to methods of making such waveguides.
Lasers are now widely used in many surgical procedures, as well as in many industrial applications, for purposes of cutting or vaporizing material in the working area. In many surgical applications of lasers, it is necessary to provide high power density at the working area, e.g., for cutting or ablating tissue. It is also necessary or desirable, in many surgical applications, to deliver the laser energy at different distances from the distal tip of the waveguide without losing substantial power density. However, the laser energy exiting from the conventional waveguide diverges, thereby decreasing the output power density at the working area according to the distance of the working area from the distal tip of the waveguide. Various techniques have heretofore been proposed for concentrating laser energy in the working area, such as lenses, but such techniques are not applicable, or are applicable only with great difficulty, when used with laser waveguides for transmitting relatively high powers.
Recent advances, such as described in our prior U.S. Pat. No. 4,930,863, provide hollow waveguides for delivering laser energy of relatively high power. In such hollow waveguides, however, the laser energy exiting from the waveguide also undergoes a divergence which reduces the power density delivered to a working area as a function of the distance of the working area from the output tip of the waveguide.